12BH7 LONG PLATE BRIMAR MATCHED PAIR VALVES TUBES NOS?

Pair Brimar Valves/Tubes   2 x Triode   Type  12BH7

Type		12BH7
Make		Brimar STC in England.
Labelling		Brimar BVA Made in England
Coding		4E9/1585 on both
Getter, Anode		Large Circular Top Halo Getter.  Anodes 17mm long black ladder.
Base/Pins		B9A
Date		Approx 1960
Condition		Probably unused.  See measurements below and picture of actual tubes/valves. Figures span the average new values for current and equal and above for gain.   Matching is very good for this type.  They are difficult to find and select! Almost identical values for each and gain figures equal to average new; currents equal or above average.
Box		White Box
TEST DATA
Parameter	Value	Test Results -
Va	250
Vh	6.3
-Vg	10.5
Average New Value		Valve No 25		Valve No 26
Ia	11.5	14.2	11.5	14.2	11.9
gm	3.1	3.05	3.1	3.1	3.1

Detail of anodes on actual items.

Notes:-  The "NewValue" column indicates the settings on the AVO VCM characteristic meter and the approximate "good" readings expected from a new valve.For double valves the results for ia and gm are shown in the two columns for each valve.  All valves are tested for cathode to heater leakage and for absence of significant grid current.

Va is anode voltage. V_h is heater or filament voltage. V_g is grid voltage. I_a is anode current in mA. g_m is the mutual conductance. For Rectifiers and signal diodes the Test results for anode current are percentages of the "good" figure.

This is a clearance of some of a personal collection of all sorts of electrical and electronic items.

I am happy to respond to any electrical questions about valves - but NOT about audio quality!  

Can also test valves and provide a report using calibrated valve testers.  A charge of £1.50 per valve is made in addition to return postage.  If you require this,  please contact me via "ask seller a question".